This invention relates to a golf simulator that calculates and displays a simulated ball trajectory from an actual ball struck from a hitting area into a target screen and, more particularly, to such an apparatus having a system for determining a slice/hook component of the ball trajectory.
Several prior art devices exist for determining the amount of hook or slice imparted to a golf ball in an indoor golf playing system. These devices, however, have not been completely satisfactory in that they have been complicated in construction and expensive to manufacture, have required complex screen arrangements, have not been completely accurate or reliable in operation, and have required extensive maintenance.
In one such device, a spherical shell or screen is used and the tee for the golf ball is positioned at the center of the sphere. If the golf ball is hit without side spin, it will hit the screen and rebound therefrom to the center of the sphere. If however, a side spin is imparted to the ball, it will not return to the center of the sphere. By measuring or indicating the point to which the ball returns, the amount of spin (hook or slice) can be determined. This type of system is subject to certain disadvantages. If the ball must roll back toward the center of the sphere before its rebound position is indicated, it is subject to inaccuracies caused by the floor surface not being completely level, which may affect the roll and/or bounce of the ball. Furthermore, the construction of a perfectly spherical screen is difficult and expensive.
Another type of device uses two impact surfaces or screens positioned at an angle relative to each other. The ball is hit into one of the screens and bounces off of that screen onto the second screen. The points at which the ball strikes the first and second screens are detected to indicate the amount of spin imparted to the ball. The geometry of the two screens is such that if a ball having no side spin strikes the first screen at a first point, it will strike the second screen at a predetermined second point. If, however, side spin is imparted to the ball, it will strike the second screen at a point other than the predetermined second point, and the difference between the actual second point of contact and the predetermined point is used to determine and indicate the amount of hook or slice. This system has the obvious disadvantage that it requires two accurately positioned and constructed screens rather than a single screen. This is critical not only because of the additional expense of a second screen, but also because of the additional space required for the second screen. Space, of course, is at a premium in an indoor golf playing system. Also, the second screen may adversely affect, from the standpoint of appearance, the simulation of actual golf course playing conditions.
A third type of apparatus uses a single screen wound on two cylinders such that, as it is wrapped around one cylinder, it unwraps from the other cylinder. If a ball having a side spin is hit into the screen, it will move the screen laterally in a direction corresponding to the direction of the spin and in an amount corresponding to the amount of spin. By detecting the amount of screen that is unwrapped from one cylinder and wrapped around the other cylinder, owing to the impact of the spinning golf ball, the amount of spin and thus the amount of slice or hook can be determined and indicated. This type of apparatus has the disadvantage of being expensive and complicated in construction in that it requires two cylinders and the mechanism associated therewith for wrapping and unwrapping the screen. Furthermore, the moving parts in the screen mounting mechanism are subject to wear and thus to mechanical failure, thus requiring extensive maintenance.
In yet another apparatus, the apparatus includes an impact surface such as a wall or screen into which the golf ball is hit. A row of detectors is positioned between the point from which the ball is hit and the surface. After the ball has been hit and prior to striking the surface, it crosses the row of vertically oriented detectors to actuate one or more of them. The ball then rebounds from the surface and crosses back through the row of detectors to actuate one or more of them. In the case of a substantially planar impact surface, if the ball has no spin imparted to it, the angle of incidence of the ball with respect to the impact surface will equal the angle of reflection. Thus, when there is no spin on the ball and it is detected by one or more detectors as it travels toward the surface, there is a corresponding known detector or detectors that should be actuated as the ball rebounds from the surface. If side spin is imparted to the ball, the actual angle of reflection from the surface will differ from the angle of reflection when there is no side spin. Therefore, a ball having side spin will actuate one or more detectors other than the known detector or detectors that would be actuated when there is no side spin. By noting which detector (or detectors) is actuated by the reflected ball having side spin, the amount of hook or slice can be determined. This system is similarly subject to certain disadvantages. In particular, it is expensive to manufacture and resolution is inadequate.